\def\dashuline{\bgroup 
  \ifdim\ULdepth=\maxdimen  % Set depth based on font, if not set already
   \settodepth\ULdepth{(j}\advance\ULdepth.4pt\fi
  \markoverwith{\kern.15em
  \vtop{\kern\ULdepth \hrule width .3em}%
  \kern.15em}\ULon}

\newenvironment{relacionsinrestriccion}[2]{
\nombrerelacion{#1} ( #2 )
\begin{itemize}
}
{
\end{itemize}
\medskip
}

\newenvironment{relacion}[3] {
\nombrerelacion{#1} ( #2 )
\begin{itemize}
    #3
\end{itemize}
\begin{enumerate}
}
{
\end{enumerate}
\medskip
}

\newcommand\nombrerelacion[1] {
\textbf{#1}
}

\newcommand\clave[1] {
\underline{#1}
}

\newcommand\claveforanea[1] {
\dashuline{#1}
}

\newcommand\claveyforanea[1] {
\clave{\claveforanea{#1}}
}

\newcommand\pk {
\textbf{PK = }
}

\newcommand\ck {
\textbf{CK = }
}

\newcommand\fk {
\textbf{FK = }
}

\newcommand\set[1] {
\{ #1 \}
}
